The most important – and somewhat misunderstood – component of the Medicare statute outlines the circumstances governing coverage of medical services by the Medicare entitlement. This section of the law clearly states that a medical service or test must be reasonable and necessary for the diagnosis or treatment of an established condition, that is, where signs and symptoms of a condition are already detectable to the patient and/or doctor.  This condition in the statute expressly denies coverage where no signs or symptoms are present, but simply where there may be curiosity about risk.
To further clarify the intent of the statute, the service will only be covered where such service has value “… in the diagnosis, direct care, and treatment” of a known and clearly present condition. Such a limitation excludes the diagnostic testing for the medical risk of diseases, with only a few exceptions.  The Centers for Disease Control has published a detailed description of the limited, covered screening tests for risk. 
It is widely known that direct analysis of a patient’s chromosomes, or a patient’s genes – where personal and specific genetic information can be studied – may uncover clues to an individual’s risk of disease or the risk a person may transmit such a condition to a next generation family member.   The types of gene testing include single gene analysis (such as BRCA breast cancer tests) as well as testing for tumor response to certain types of chemotherapy.
While interesting from the point of view of medical research or family counselling, such studies of risk are largely excluded from Medicare coverage, as discussed above.
However, the well-publicized breakthroughs in the analysis of human chromosomes and DNA may lead the public to assume this technology is ready for assessment of individual patients and their current symptoms and conditions, rather than their lifetime risk of a disease which may never occur. These are two very different types of questions. Medical genetics counselling centers openly solicit patients to undergo risk assessment, especially where a family history of genetic disease is prominent; this is a common practice where there is a high genetic risk of cancer. 
However, most genetic testing which is currently marketed to Medicare beneficiaries has no value for the patient, because such testing does not apply and guide therapy for a beneficiary’s current conditions or symptoms, but provides rather for guidance on family risk, that is to individuals in the next generation. The Office of the Inspector General clarified this limitation by stating “Medicare does not pay for preventive screening tests except those specifically authorized by statute. Since CMS considers predictive tests to be screening tests, genetic tests for this purpose are not covered by Medicare.” 
To assist patients in deciding whether to undergo such testing, a Medicare administrative contractor – Novitas Solutions – has published a guide to the limited, useful DNA testing which is reasonable and necessary and covered in the Novitas jurisdiction under the Medicare statute. Of approximately 50 currently available tests, about half are covered, but only with strict conditions.  Other Medicare contractors have provided similar notice on limitations of genetic testing.
A recent analysis of the limited value of genetic testing has been published in The Annals of Internal Medicine entitled, “The Deceptive Appeal of Direct to Consumer Genetics.”  The authors point out that the recent completion of the “Human Genome Project”, a National Institutes of Health initiative to study 100% of human genes  , has created a marketing opportunity that has been taken up by commercial laboratories through “direct-to-consumer” marketing.
Such marketing must be put in a correct perspective, although, as the authors point out, developing the best policy response to misleading, direct-to-consumer marketing is a challenge.
“Riding the wave of the Human Genome Project, several companies now offer direct-to-consumer (DTC) genetic testing. Their marketing messages are built on the rhetoric of leading scientists: A person’s genome is an “instruction book”, and deciphering it can contribute to the transformation of medicine from a reactive to a proactive science, in which genetic risk information informs disease prevention. This intuitively appealing and seemingly logical claim is bolstered by a vision of genetic information as more accurate, cutting-edge, and meaningful than other kinds of health information.”
The mapping of the human genome is one of the monumental achievements of science. However, as of yet, the utility of the information in this project for the promise of the Medicare statute to mitigate explicit illness, signs, and symptoms of disease must be considered limited at best.